The invention relates to a printing unit having at least one press unit with at least one forme cylinder, a transfer cylinder, an inking unit, and a damping unit, the inking unit of each press unit applying printing ink to a forme cylinder of the respective press unit in such a way that a ductor roll of an inking unit picks up printing ink from an ink fountain, the printing ink being applied to the forme cylinder of the respective press unit by a film roll interacting with the ductor roll, by inking unit rolls arranged downstream of the film roll and by at least one ink applicator roll rolling on the forme cylinder. Furthermore, the invention relates to an inking unit for a press unit of a press applying printing ink to a forme cylinder of the press unit such that a ductor roll of an inking unit picks up printing ink from an ink fountain, the printing ink being applied to the forme cylinder of the press unit by a film roll interacting with the ductor roll, by inking unit rolls arranged downstream of the film roll and by at least one ink applicator roll rolling on the forme cylinder.
Printing units of web-fed rotary presses, in particular of newspaper presses, have a plurality of press units, each press unit comprising a transfer cylinder, a forme cylinder and an inking unit and also a damping unit. Oil-less press units without a damping unit are also known. Moreover, such press units may have impression cylinders, an impression cylinder being able to interact with one or more transfer cylinders of different press units. In addition to press units which have impression cylinders of this type, press units are also known which have no impression cylinder, the transfer cylinders of two press units rolling on each other in the case of such printing units without impression cylinders. As a rule, rubber blankets are stretched onto the transfer cylinders and printing plates are clamped onto the forme cylinders, for which reason the transfer cylinders are also designated blanket cylinders and the forme cylinders are also designated printing plate cylinders.
The inking unit of a press unit is used to apply printing ink to the forme cylinder of the press unit and the damping unit is used to apply a damping solution to the forme cylinder of the press unit. The prior art already discloses a series of inking units with which printing ink is applied effectively to a forme cylinder. As prior art, reference should be made here to U.S. Pat. No. 6,279,473 and DE 101 58 487 A1.
Inking units known from the prior art have a ductor roll, which picks up printing ink kept ready in an ink fountain of the inking unit and transfers it to a film roll. From the film roll, the printing ink is transported in toward the forme cylinder of the press unit by a plurality of inking unit rolls arranged downstream of the film roll. The inking unit rolls that roll on the forme cylinder are designated ink applicator rolls. In the inking units known from the prior art, at least some of the inking unit rolls arranged between the film roll and the or each ink applicator roll are driven so as to rotate and to oscillate at the same time. Because of the rotary drive, inking unit rolls rotate about their longitudinal central axis, and the same are moved to and fro along their longitudinal central axis in response to an oscillating drive. In the case of all the inking units known from the prior art, at least some of the inking unit rolls that are driven in rotation are also driven in oscillation. According to the prior art, all the inking unit rolls driven in oscillation are also driven in rotation. Because, the inking unit rolls driven in oscillation are also driven in rotation, the inking units and printing units and the associated drives require complex construction.